1. Field of the Invention
This invention relates generally to a system and method for determining vehicle wheel misalignment and, more particularly, to a system and method for determining vehicle wheel misalignment that includes algebraically accumulating the hand-wheel position over a sampling period to determine if the averaged hand-wheel position is significantly turned.
2. Discussion of the Related Art
When a vehicle is manufactured, the orientation of the front wheels of the vehicle is calibrated to provide optimum steering performance and handling of the vehicle. However, various factors, such as wear and tear of the suspension components, age of the vehicle, impacts with, for example, pot holes and parking lot stops, etc., may cause the front wheels of the vehicle to become misaligned, which could affect steering performance and vehicle stability. An indicator typically used to determine wheel misalignment under straight-ahead driving conditions is whether the hand-wheel is centered. If a vehicle's front wheels are misaligned, the vehicle operator can overcome the misalignment by turning the hand-wheel enough so that the vehicle tracks in a straight ahead direction. Because vehicle misalignment has a potential impact on vehicle performance and stability, it is desirable that the vehicle operator be informed of the wheel misalignment so that the vehicle can be serviced and the alignment corrected.
For some wheel misalignment occurrences, such as a severe impact with a pothole, the wheel misalignment may be sufficiently dramatic so that the vehicle operator will immediately notice that the wheel misalignment has occurred and can have the vehicle serviced. However, most wheel misalignments are relatively minor, where it would not be noticed by the vehicle operator, but still could have significant affects on wheel wear and vehicle stability.
It is known in the art to determine vehicle wheel misalignment, and provide an indication to the vehicle operator of the misalignment. For example, U.S. Pat. Nos. 6,574,539 and 6,650,980, both titled Steering-Wheel Torque-Based Detection of Misalignment of a Vehicle Steering System, disclose such a system that makes use of torque measurements when a vehicle is driven straight to determine whether or not the wheels are misaligned. However, the wheel misalignment detection systems disclosed in these patents use fairly complicated processes. Simpler systems for providing wheel misalignment detection can be provided.